Big data are characterized by three “V” as Volume (bulk), Variety (diversity) and Velocity (high speed) (for example, see nonpatent literature 1). Recently, it has been widely recognized that extraction of information from mass data has the value. By communicating and cooperating data among different types of business and analyzing, it is possible to acquire new knowledge, create new business in a corporation and realize improvement of efficiency of the social system. These are data originated from persons and the total amount of data produced is of the order that is limited by the scale of a population. However, in the future, sensors and measuring instruments are massively introduced in the society as represented by M2M (Machine-to-Machine) service and mass various data are produced every moment from them. Therefore, it is necessary to make sure of appropriate data source among various data sources (for example, see nonpatent literature 1).
Weight percentage of substances that a person takes in a lifetime are substances inhaled (83%), drinks (8%) and food (7%) in descending order. Among substances inhaled, “air in his or her home” occupies mostly. It occupies 56% of the total weight of substances that a person takes in a lifetime and has a large effect on life. A house is exactly the second womb environment in this context, so we need to pay more attention to “air in his or her home” (for example, see nonpatent literature 2). Invasion of foreign bodies into the body of a person is blocked at the front by keratin of skin and mucous membranes of the throat and the intestines. And if they fail to block, the foreign bodies are eliminated by phagocytosis of neutrophil and macrophage. Clean air is important from the point of view of immunology regardless.
On the other hand, conventionally, as a method of detecting the sleeping state of inpatients in a general ward of a hospital, tenants in institutions for the aged (nursing care homes for the aged) or members of a general family and ascertaining the health state, known are a method of photographing an inpatient or a tenant with a video camera during sleep and a method of attaching a clinical thermometer, a pulsimeter, a pulse oximeter, etc. to them and measuring temperature, a pulse rate, oxygen saturation, etc. Developed also is a system that uses a sheet-like two-dimensional pressure sensor and obtains information when a person lowers his legs to the floor from a bed and information of posture on a bed during sleep.